[PO-N2] Poster Session 2

[P2-77] EXPERIMENTAL AND DENSITY FUNCTIONAL THEORY STUDIES OF PRECIPITATE INTERFACES IN ALUMINIUM ALLOYS, WITH FOCUS ON β" & β

^○Haris Rudianto, Deni Hariadi, Andriansyah Andriansyah (Gunadarma University, Indonesia)

Aluminium is the third most abundant element in the Earth’s crust, after oxygen and silicon. Before the start of the last century, aluminium started to come into wide use as a structural material. Since then, it has reached the position of being the second most used metal in the world, with only steel beating it to the throne. One important structural limitation of aluminium is their fatigue strength. Precipitation hardening is utilized to strengthen a wide variety of alloy systems especially for Aluminum Alloys. An example is the class of commercially important Al-Mg-Si based alloys which are strengthened by a number of metastable precipitate phases, where the needle-shaped β’’-Mg5Si6 precipitates are often the main contributor to hardening. Beginning with the supersaturated solid solution (SSS), the generic precipitation sequence in Al-Mg-Si alloys is generally believed to be :



SSS -> Mg/Si clusters -> Guinier-Preston zones -> β^’’ -> β^’ ->β



In practice, the sequence can be even more complex and a number of other metastable phases, depending on alloy composition and the heat treatment time and temperature. In this research, interface energy was calculated by Quantum Espresso with super cells designed on VESTA. For comparison, in this research, experimental was also carried out to determine effects of strengthening precipitates on mechanical properties. T6 heat treatment was done starting from solid solution treatment, quenching and finished my artificial aging. Hardness was done to determine mechanical properties and SEM-EDS and XRD were done to characterize the materials.



Keywords; Aluminum Alloys, DFT, Strengthening Precipitates, Heat Treatment